Organic veggies?

Is there a place to get organic veggies (grown without chemical pesticides/fertilizer)?
They don’t have to be certified, as long as the grower or vendor is trustworthy. I did worry about it too much last time I was there as everything was new to me, but I’d at least like to support farmers that are making an effort not to poison us and everything else.

Every Saturday morning downtown a half-block from our home at the Eco-Tianguis Sanka in the small plaza in front of the Escuela Primaria "Vicente Guerrero" across the street from the Museo Arqueológico de la Costa Grande.